摘要
安塞县在我国北方农牧交错带具有代表性 ,尤其在环境脆弱、人口密度、食物安全、土地利用等方面更具典型性。安塞县土地垦率高 ,坡耕地比例大 ,坡度陡竣 ,耕地对粮食生产限制多。受温度、降水和土地条件的制约 ,粮食生产的潜力难以实现。长期以来粮食生产率低而不稳。通过加大投入 ,虽然单产有一定的提高 ,但产量波动幅度也不断加大。不同人口控制方案下2 0 0 0～ 2 0 30年粮食生产率胁迫力计算结果表明 ,靠大幅度提高单产 ,实现少种自给 ,同时退耕还林 (草 ) ,这一似乎理想的途径并不现实。考虑到粮食生产的环境代价和国内外目前粮食市场的调剂能力 ,这一“理想”途径也不划算不可取。只有严格控制人口增长 (不应超过 2 .0胎 ) ,在此基础上确定适当的粮食自给水平 (不应超过 80 % ) ,保持粮食生产率胁迫力为负值或较短时间较小的正值 ,才能真正实现退耕还林 (草 )和改善生态环境。
Ansai county stands for ecotone of agriculture and animal husbandry of China. It is also typical representative county with the particular aspects of ecologically fragile environment, population density, food security, land use and so on. In Ansai county, the ratios of reclaimed and cultivated land and the proportion of hillside fields to cultivated land are high, the cultivated lands restrictive factors about food production are too many. The land productive potentialities can not fully bring out because it is restricted by the temperature, precipitation and land structure. The food productivity is low and unstable for a long time. The land productivity is raised through putting in much labor, capital and materials, but it is still unstable. The calculating results of land productivity stress within 2000～2030 with different population scenarios make known: It is as if ideal but unrealistic way that accomplishing less cultivated land and food self-reliance in the same time returning cultivated land to wood and grass land, which depend on large increasing land productivity. If the environmental costs of food production in the county and the adjusting capability of international and domestic food markets are taken into account, the “ideal way” is not worthwhile and not recommendable. Only when the rational food self-reliance percentage (no more than 80%) is determined on the basis of controlling population growth rigorously (no more than 2.0 birth), and keep the value of land productivity stress less than zero or very little in short time, “returning cultivated land to wood and grass land” and improving ecological environment will be facilitated factually.
出处
《水土保持学报》
CSCD
北大核心
2000年第z1期98-103,共6页
Journal of Soil and Water Conservation
基金
中科院水保所安塞站科技部中西部专项
国家"九五"科技攻关专题 !( 96-0 0 4 -0 5-0 4 )安塞试区部分成果
关键词
农牧交错带
人地关系平衡模型
粮食生产率胁迫力
ecotone of agriculture and animal husbandry
man-land equilibrium model
stress of land productivity
